Interface SplittableCompressionCodec

This interface is meant to be implemented by those compression codecs
which are capable to compress / de-compress a stream starting at any
arbitrary position.
Especially the process of de-compressing a stream starting at some arbitrary
position is challenging. Most of the codecs are only able to successfully
de-compress a stream, if they start from the very beginning till the end.
One of the reasons is the stored state at the beginning of the stream which
is crucial for de-compression.
Yet there are few codecs which do not save the whole state at the beginning
of the stream and hence can be used to de-compress stream starting at any
arbitrary points. This interface is meant to be used by such codecs. Such
codecs are highly valuable, especially in the context of Hadoop, because
an input compressed file can be split and hence can be worked on by multiple
machines in parallel.